Structure and functional expression of a member of the low voltage-activated calcium channel family

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Science  21 May 1993:
Vol. 260, Issue 5111, pp. 1133-1136
DOI: 10.1126/science.8388125


Oscillatory firing patterns are an intrinsic property of some neurons and have an important function in information processing. In some cells, low voltage-activated calcium channels have been proposed to underlie a depolarizing potential that regulates bursting. The sequence of a rat brain calcium channel alpha 1 subunit (rbE-II) was deduced. Although it is structurally related to high voltage-activated calcium channels, the rbE-II channel transiently activated at negative membrane potentials, required a strong hyperpolarization to deinactivate, and was highly sensitive to block by nickel. In situ hybridization showed that rbE-II messenger RNA is expressed in regions throughout the central nervous system. The electrophysiological properties of the rbE-II current are consistent with a type of low voltage-activated calcium channel that requires membrane hyperpolarization for maximal activity, which suggests that rbE-II may be involved in the modulation of firing patterns.

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